The Tissue Procurement Core in conjunction with the Molecular Core Facility is housed in a 3,000 sq. foot laboratory facility located in Barnes- Jewish Hospital North Kinghighway building. The Core maintains equipment for tissue processing, sample storage, and database maintenance. This includes specimen freezing baths, two ultralow mechanical freezers, two microtome, equipment and supplies for standard histological staining, and a standard light microscope. The Core is also equipped with basic instruments for the preparation and electrophoretic analysis of nucleic acids. Two Pentium-based computers (one workstation and one laptop unit) are used for data entry and retrieval. In addition, the Core maintains and operates a pixcell II laser-capture microdissection microscope that is available for investigator use. The Core is directed by Dr. Mark A. Watson, a board certified clinical pathologists and an NCI-funded investigator with research interests in gene expression profiling, molecular cancer diagnostics, and the molecular biology of breast cancer.. As director of the Core, he is responsible for supervising most aspects of its day-to-day operation including: supervision of research assistants in tissue and macromolecule processing, quality control of molecular preparations, developing and updating procedures and laboratory equipment for macromolecular processing of specimens, administering investigator requests for patient specimens, administering investigators requests for patient specimens, and designing, implementing, and updating the Core's specimen database and web site. The Core is staffed by 2.5 full time employee equivalents. Victoria Holtschlag, B.S., administration of the laboratory. This includes accepting requests from investigators, preparing molecular and histological specimens for studies (DNA, RNA, frozen sections, paraffin embedded sections), updating protocols, ordering, billing, and laboratory maintenance. In consultation with the director(s), Ms. Holtschlag organizes projects and performs quality assurance (histological and molecular) of specimens. She also assists investigators in the training and use of the Laser Capture Microdissection instrument. Ms. Holtschlag is a certified medical technologist with over twenty years of experience in administering and supervising clinical laboratories. In addition to specimen procurement for specific studies, the Core maintains an archive of several thousand frozen tissue specimens (non- malignant and tumor tissue) collected from routine surgeries. This includes over 1,000 gastrointestinal tumor specimens. Pathology and limited demographic data is available for all specimens. Many tissues are collected as non-anonymized specimens from patients who have signed full informed consent for the Core to obtain follow-up clinical information based on maintained patient identifiers. Investigators may received coded clinical and follow-up data on "as-needed" basis. For almost all requests patient specimens are processed to DNA, RNA, or cut as histological sections. A representative section of the specimen is also sectioned and stained to confirm pathological diagnosis and are qualitatively assess the tissues for percent necrosis and tumor cell content. Isolated nucleic acids are qualitatively assessed by agarose gel electrophoresis and quantified by UV absorbence. This quality controlled material is then distributed to the requesting investigator where it can be immediately used for biochemical or genetic analysis.